When I looked it up, I read that most schools start accepting applications at the beginning of September but this video says October. Which is it?

Honestly, I'd advise that you take a break or lessen the intensity of your studying. I know it sounds counterproductive, but it helps. That's the advice I received, and it worked. Seeing my scores decline was discouraging and made me more anxious to improve. It increased my pressure to perform--making me do worse. It was demoralizing. I was fed up and decided only to review my notes and strategies, and do short focused drills for much less time than I'd been doing. I reviewed old lessons just to keep the fundamentals fresh in my mind. I did this for about 2 weeks before taking the actual LSAT because I didn't want to be fried mentally when taking the test. I scored 8 points higher on the actual LSAT than on my last practice test. Your brain probably needs a little respite to break the plateau. I also think changing your studying environment can help. I always studied at the desk in my room since that's where I'd be taking the exam (which can be helpful), but changing it up sometimes by going to different coffee shops, a university, a library, etc. helped break the monotony and enhance my motivation, energy, and overall productivity. Praying for you! You've got this!

Just submit it if it's ready. Many schools offer the option to indicate when your score will be released and LSAC will send it to them. If the school doesn't have that option just email the admissions office to let them know your score is forthcoming. I think it'll be faster that way.

Is the flawed reasoning not:

A ‑m→ B ‑m→ C

A ‑m→ C

if you replace "most" with the biggest subset in the superset or in the case of answer choice A, the subset of most injuries in the superset? That's how I spotted A.